wcst_import nil_value is nan and has error

[Bang Pham Huu]

  return self._resolve(expression, evaluator_slice.get_dataset())
  File "/home/rasdaman/install/share/rasdaman/wcst_import/master/evaluator/gdal_expression_evaluator.py", line 72, in _resolve
    for band in gdal_dataset.get_fields_range_type():
  File "/home/rasdaman/install/share/rasdaman/wcst_import/util/gdal_util.py", line 195, in get_fields_range_type
    nil_value =  str(int(math.floor(float_value))) + ":" + str(int(math.ceil(float_value)))
ValueError: cannot convert float NaN to integer